The overall research objectives of the FRIENDS Children's Environmental Health Center are to: (1) study the impact of exposure to polychlorinated biphenyls (PCBs) and methylmercury (McHg) on cognitive, sensory and motor development of children, (2) develop effective educational strategies to reduce exposure to these neurotoxic contaminants, and (3) undertake laboratory studies to better understand the mechanisms by which these contaminants induce neurological deficits in children. The Center will build on several long-standing research collaborations and will be organized around an exposure cohort that is already being recruited. The cohort consists of Hmong and Laotian refugees who are consuming PCB- and MeHg- contaminated fish from the Fox River in northeastern Wisconsin. The Center includes an administrative core, a community-based project, two biomedical research projects and an analytical toxicology core. The two primary goals of the community-based project are: (1) to evaluate the impact of PCB and MeHg exposure on reproductive health and child development and (2) to provide families with practical information that will help them to reduce their exposure to PCBs and MeHg. The assessments of the children will focus on specific aspects of behavioral and sensory function that have not been adequately addressed in previous human studies. These goals will be accomplished in partnership with community resource groups in the area. The biomedical research projects will complement the community-based project by characterizing the cognitive, sensory, motor and neurochemical effects of exposure to PCBs alone, MeHg alone or PCBs and MeHg combined in a rodent model. Moth projects will used a mixture of PCBs that models the PCB congener profile in Fox River fish, and a ratio of PCBs to MeHg similar to that found in the fish. The findings from the animal studies will guide the selection of additional behavioral and sensory endpoints for use in the children exposed to PCBs and MeHg via maternal consumption of Fox River fish. The analytical toxicology will formulate the PCB mixture to be used in the animal studies and provide congener specific PCB analysts, heavy metal analysis, and pesticide analysis in human and animal samples from the three research projects. The administrative core will provide oversight, coordination and integration of all Center activities.